Perhaps the most ubiquitous example of light signaling are traffic lights. A typical traffic light include three light sources, corresponding to distinct signals directed at motorists and pedestrians. While some geographical variations exists, typical traffic signal includes a set of red, orange/yellow and blue/green light. Each of these light sources are housed in individual or common protective cases. The cases protect the light sources from the weather but also provide shade to improve the visibility of the light under bright conditions.
The light sources are usually incandescent light bulbs fitted with colored filters, or monochromatic LED units. LED traffic lights have the same general illumination performance as traditional bulbs but present several major advantages over incandescent bulbs. The first advantage of these LED traffic lights is their durability. They typically need to be replaced every 15 years, compared to 1-2 years for incandescent bulbs. A second major advantage of using LED in traffic lights is their very low energy consumption. An array of LED's use only 10%-30% as much energy as an incandescent bulb for a similar light output. This energy conservation can save municipalities, and other entities in charge of signal lights, a significant expense in electricity and maintenance.
Despite the superior performance of the monochromatic LED arrays over incandescent lights, a new generation of LED, multi-colored (RGB) LEDs display an even greater potential. Multicolored light displays using monochromatic LED need to be composed of individual overlapping arrays to display each desired color or to have array composed of sets of multiple monochromatic LEDs. One LED of each color for each point to be illuminated. In contrast, multi-colored (RGB) LEDs are able to generate multiple color from a single part, dramatically reducing the number of electronic components and the risk of failure. More importantly, multi-colored (RGB) LEDs use significantly even less energy than monochromatic LEDs, allowing the production of full-colored display and signals with extremely low operating costs.